# US 2023/0276711 A2 · Piezoelectric laminate, production method for piezoelectric laminate, and piezoelectric element

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- Number: US 2023/0276711 A2
- Document ID: US20230276711A2
- Status: Published application
- Kind: A2
- Application number: 17/917,055
- Filed: 2021-02-24
- Published: 2023-08-31
- Earliest claimed: 2020-04-06
- Assignees: Sumitomo Chemical Company, Limited
- Applicants: Sumitomo Chemical Company, Limited
- Inventors: Toshiaki KURODA; Kenji SHIBATA; Kazutoshi WATANABE; Takeshi KIMURA
- Web page: https://patentgrep.com/patent/US20230276711A2

## CPC

- B06B 1/0611: {in a pile}
- H10N 39/00: Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00
- B06B 1/0261: {taken from a transducer or electrode connected to the driving transducer}
- G01H 11/08: using piezoelectric devices
- H10N 30/076: by vapour phase deposition
- H10N 30/082: by etching, e.g. lithography
- H10N 30/101: {with electrical and mechanical input and output, e.g. having combined actuator and sensor parts}
- H10N 30/20: with electrical input and mechanical output, e.g. functioning as actuators or vibrators
- H10N 30/704: {based on piezoelectric or electrostrictive films or coatings}
- H10N 30/853: Ceramic compositions
- H10N 30/8542: {Alkali metal based oxides, e.g. lithium, sodium or potassium niobates}
- H10N 30/88: Mounts; Supports; Enclosures; Casings
- B06B 1/0622: {on one surface}
- B06B: METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, {e.g.} FOR PERFORMING MECHANICAL WORK IN GENERAL (for particular applications, see the relevant subclasses, e.g. B07B1/40, B23Q17/12, B24B31/06; measurement of mechanical vibrations G01H; in direction finding, locating, distance or velocity measuring G01S; {generating seismic energy G01V1/02}; control of mechanical vibrations in general G05D; sound-producing devices, e.g. bells, sirens, whistles G10K, {e.g. methods or devices for transmitting, conducting, or directing sound in general G10K11/00}; generation of electrical oscillations H03B; electromechanical resonators in general H03H; electromechanical transducers {for communication techniques, e.g. microphones, speakers} H04R)
- H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- G01H: MEASUREMENT OF MECHANICAL VIBRATIONS OR ULTRASONIC, SONIC OR INFRASONIC WAVES

## Abstract

There is provided a piezoelectric stack, including: a substrate; an output-side bottom electrode film on the substrate; an output-side piezoelectric film, being an oxide film, on the output-side bottom electrode film; an output-side top electrode film on the output-side piezoelectric film; an input-side bottom electrode film on the substrate; an input-side piezoelectric film, being a nitride film, on the input-side bottom electrode film; an input-side top electrode film on the input-side piezoelectric film; and an ultrasonic output part and ultrasonic input part placed in such a manner as not overlapping each other when viewed from a top surface of the substrate, the ultrasonic output part comprising a stacked part of the output-side bottom electrode film, the output-side piezoelectric film, and the output-side top electrode film, the ultrasonic input part comprising a stacked part of the input-side bottom electrode film, the input-side piezoelectric film, and the input-side top electrode film.

## Claims

### Claim 1

A piezoelectric stack comprising:
a substrate;
an output-side bottom electrode film on the substrate;
an output-side piezoelectric film, being an oxide film, on the output-side bottom electrode film;
an output-side top electrode film on the output-side piezoelectric film;
an input-side bottom electrode film on the substrate;
an input-side piezoelectric film, being a nitride film, on the input-side bottom electrode film;
an input-side top electrode film on the input-side piezoelectric film; and
an ultrasonic output part and ultrasonic input part placed in such a manner as not overlapping each other when viewed from a top surface of the substrate,
the ultrasonic output part comprising a stacked part of the output-side bottom electrode film, the output-side piezoelectric film, and the output-side top electrode film,
the ultrasonic input part comprising a stacked part of the input-side bottom electrode film, the input-side piezoelectric film, and the input-side top electrode film.

### Claim 2 (depends on 1)

The piezoelectric stack according to claim 1, wherein the ultrasonic output part and the ultrasonic input part are not in contact with each other.

### Claim 3 (depends on 1)

The piezoelectric stack according to claim 1, wherein the output-side piezoelectric film, being a deposited film, contains any one of potassium sodium niobium oxide, lead-zirconium-titanium oxide, bismuth sodium titanium oxide, or bismuth ferrite.

### Claim 4 (depends on 1)

The piezoelectric stack according to claim 1, wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride.

### Claim 5

A method of manufacturing a piezoelectric stack, comprising:
depositing an output-side bottom electrode film and an input-side bottom electrode film on a substrate;
depositing an output-side piezoelectric film, being an oxide film, on the output-side bottom electrode film;
depositing a protective film that protects the output-side piezoelectric film;
depositing an input-side piezoelectric film, being a nitride film, on the input-side bottom electrode film;
exposing the output-side piezoelectric film by removing the protective film by etching; and
depositing an output-side top electrode film on the output-side piezoelectric film and depositing an input-side top electrode film on the input-side piezoelectric film, thereby
producing a stack in which an ultrasonic output part and an ultrasonic input part are placed in such a manner as not overlapping each other when viewed from a top surface of the substrate,
the ultrasonic output part comprising a stacked part of the output-side bottom electrode film, the output-side piezoelectric film, and the output-side top electrode film,
the ultrasonic input part comprising a stacked part of the input-side bottom electrode film, the input-side piezoelectric film, and the input-side top electrode film.

### Claim 6 (depends on 5)

The method of manufacturing a piezoelectric stack according to claim 5, wherein the protective film is any one of a film containing silicon dioxide, a film containing lanthanum nickel oxide, or a film containing strontium ruthenium oxide.

### Claim 7 (depends on 1)

A piezoelectric element comprising:
the piezoelectric stack according to claim 1;
a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and
a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,
wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.

### Claim 8 (depends on 2)

The piezoelectric stack according to claim 2, wherein the output-side piezoelectric film, being a deposited film, contains any one of potassium sodium niobium oxide, lead-zirconium-titanium oxide, bismuth sodium titanium oxide, or bismuth ferrite.

### Claim 9 (depends on 2)

The piezoelectric stack according to claim 2, wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride.

### Claim 10 (depends on 3)

The piezoelectric stack according to claim 3, wherein the input-side piezoelectric film, being a deposited film, contains aluminum nitride.

### Claim 11 (depends on 2)

A piezoelectric element comprising:
the piezoelectric stack according to claim 2;
a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and
a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,
wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.

### Claim 12 (depends on 3)

A piezoelectric element comprising:
the piezoelectric stack according to claim 3;
a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and
a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,
wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.

### Claim 13 (depends on 4)

A piezoelectric element comprising:
the piezoelectric stack according to claim 4;
a voltage applicator connected between the output-side bottom electrode film and the output-side top electrode film; and
a voltage detector connected between the input-side bottom electrode film and the input-side top electrode film,
wherein the output-side piezoelectric film deforms under a voltage application from the voltage applicator applying a predetermined electric field between the output-side bottom electrode film and the output-side top electrode film, and ultrasonic waves generated due to a deformation of the output-side piezoelectric film are transmitted from the ultrasonic output part, and the ultrasonic input part receives the ultrasonic waves reflected by a test object, and a voltage generated between the input-side bottom electrode film and the input-side top electrode film due to a deformation of the input-side piezoelectric film is detected by the voltage detector.